Electromagnetic Armor, EMA, has been shown to defeat shaped charge jets and other anti-armor threats, Typical EMA has an energy storage device, typically a capacitor(s), connected electrically in series with a set of spaced plates or rails. The anti-armor threat acts as the electrical switch for the energy storage device, discharging the energy, in the form of an electric current, electric and magnetic fields, through the anti-armor threat. The electrical energy then disrupts the shaped charged jet by Joule heating the anti-armor threat, inciting magneto-hydrodynamic instabilities in the shaped charge jet, or exciting inherent plastic instabilities in the shaped charge jet through capillary waves on the jet surface. The electrical energy may also introduce large Lorentz forces on the anti-armor threat by judicious geometry design of the rails and/or plates. This Lorentz force drives capillary waves on the shaped charge jet and will induce rotation in other anti-armor threats.
Explosive Reactive Armor, ERA, is also effective against anti-armor threats. ERA consists of two parallel plates of armor sandwiched about a shock sensitive explosive. The plates are oriented such that the surface normal to the front plate is at an oblique angle to the shot line of the anti-armor threat. A shock wave is sent through the front plate, into the explosive sandwich as the anti-armor threat strikes the front plate. The shock sensitive explosive is initiated and rapidly undergoes complete detonation. The chemical energy released during the detonation process causes the two armor plates to move apart, roughly parallel to the surface normal and obliquely to the anti-armor threat shot line. The result is that relatively thin armor plates greatly disrupt shaped charge jets and cause large rotations and even fracture of other types of anti-armor threats.